Inertial sensor, method for manufacturing inertial sensor, inertial measurement unit, portable electronic apparatus, electronic apparatus, and vehicle

Abstract

A gyro sensor includes a plurality of beams connected via a turnaround part. A groove is provided on a main surface of at least one beam of the plurality of beams. Wall thicknesses on the main surface of two sidewalls facing each other of the groove in a direction orthogonal to a longitudinal direction of the beam satisfy 0.9≤T1/T2≤1.1, where T1 is the wall thickness of one sidewall and T2 is the wall thickness of the other sidewall.

What is claimed is: 
     
       1. An angular velocity sensor comprising:
 three directions orthogonal to each other being defined as an X direction, a Y direction, and a Z direction; 
 a substrate; 
 a fixed detection electrode disposed above the substrate; and 
 a sensor structure having:
 a mass being movable along the Y direction; 
 a first fixed member fixed to the substrate; 
 fixed drive electrodes fixed to the substrate; 
 a movable drive electrode connected to the mass and arranged between the fixed drive electrodes in the Y direction; 
 a movable detection electrode that is substantially plate-shaped on a plane along the X direction and the Y direction and that is connected to the mass, the movable detection electrode facing the fixed detection electrode along the Z direction; 
 a first elastic member connecting the mass and the first fixed member, the first elastic member being configured with:
 a first beam and a second beam extending along the X direction and being parallel to each other along the Y direction, the first beam having a first surface along a plane along the X direction and the Y direction; 
 a joint connecting the first beam and the second beam, the joint extending along the Y direction; 
 a groove provided in the first surface of the first beam and provided as a recessed structure with a closed bottom and opening at the first surface, the groove extending along the X direction; and 
 two sidewalls provide on both sides of the groove along the Y direction, 
 
 
 wherein a width along the Y direction of the groove is larger than a width along the Y direction of each of the two sidewalls. 
 
     
     
       2. The angular velocity sensor according to  claim 1 , wherein
 the X direction is a longitudinal direction of the first beam. 
 
     
     
       3. The angular velocity sensor according to  claim 1 , the sensor structure further comprising:
 a second fixed member, third fixed member, and a forth fixed member fixed to the substrate; 
 a second elastic member connecting the mass and the second fixed member; 
 a third elastic member connecting the mass and the third fixed member; and 
 a fourth elastic member connecting the mass and the fourth fixed member, 
 wherein the first elastic member, the second elastic member, the third elastic member, and the fourth elastic member are connected to four corners of the mass, respectively. 
 
     
     
       4. The angular velocity sensor according to  claim 1 , wherein
 the recessed structure has a curved surface. 
 
     
     
       5. An inertial measurement unit comprising:
 the angular velocity sensor according to  claim 1 ; 
 an acceleration sensor; and 
 a control unit which controls the angular velocity sensor and the acceleration sensor. 
 
     
     
       6. An electronic apparatus comprising:
 the angular velocity sensor according to  claim 1 ; and 
 a control unit which performs control based on a detection signal outputted from the angular velocity sensor. 
 
     
     
       7. A vehicle comprising:
 the angular velocity sensor according to  claim 1 ; and 
 an attitude control unit which controls an attitude, based on a detection signal outputted from the angular velocity sensor.